Multibreak electric switch



p 1932- c. o. AINSWORTH 1,378,657

IULTIBREAK ELECTRIC SWITCH Filed May 51, 1930 I 2 Sheets-Sheet 1 Z? 25 O /a0 Sept. 20, 193 2.

C. D. AINSWORTH uum'mnmx ELECTRIC SWITCH Filed May 31, 1930 2 Sheets-Sheet 2 f71U871?01". Q m 1 Patented Sept. 20, 1932 UNITED STATES PATENT OFFICE CHESTER D. AINSWORTH, OF WOLLASTON, MASSACHUSETTS, ASSIGNOR T CONDIT v ELECTRICAL MANUFACTURING CORPORATION, OF SOUTH BOSTON, MASSACHUSETTS,

A CORPORATION OF MASSACHUSETTS MULTIIBBEAK ELECTRIC swrrcrr Application fll ed May 81, 1930. Serial No. 458,875.

This invention relates to electric switches and contact structures therefor and particularly to switches wherein the final circuit interruption takes place at a plurality of a serially-connected arcing contact members.

In the usual down break switch, consisting of a pair of vertical conducting studs and a bridging member which connects the studs at their lower ends, the magnetic flux surrounding-the studs and the bridging member tends to force apart the cooperating contact members, and particularly the resiliently mounted arcing contact members, especially upon passage of heavy current through the switch. It

constitutes an object of the present invention to provide an improved arrangement of movable arcing or contact members and associated current conducting parts in series therewith, by which the conducting parts are caused to react magnetically on the movable arcing members to'urge them into engagement with their cooperating fixedcontacts, thus tov overcome the oppositely acting magnetic effect of the current traversing'the generally U-shaped path through the switch.

A further object of the invention is to provide a contact structure as above described for a switch having four serially-connected sets of cooperating contact members.

In a copending application, Serial 'No.

242.666, filed December 27. 1927, which eventuated into Patent No. 1,762,604, issued June 10, 1930, I have described and claimed a switch having current reactive loops in the vicinity of and including the movable contact members, and it is a further object to utilize this principle in multi-break switches which are adapted to carry heavy currents, and to provide an improved loop construction which is capable of withstanding these heavy currents.

A still further object is generally to improve the construction of electric switches and contact structures therefor. 1

Fig. 1 is an end elevation of the stationary and movable switch members of an electric switch embodying the invention.

Fig. 2 is a side elevation of Fig. 1. d Fig. 3 is a plan view of the movable bridg-v ing member of Figs. 1 and 2, the switch rod being shown in section.

Fig. 4 is a detail of a movable arcing contact member and the supporting means there- Fig. 5 is a perspective view of the supportingbracket for a movable arcing contact member.

Fig. 6 is a diagrammatic representation of the current path through the switch just subsequent to the opening of the main contact members.

The switch here shown as embodying the invention includes two stationary switch members which depend from a switch frame,

not shown, and which comprise the spaced pairs of insulated studs 10 and 12 which are separately electrically connected at their lower ends by contact blocks 14 and 16, respectively, which support the stationary main, contact members of the switch. Said stationarymain contact members are of the inverted, or non-reactive, brushtype and comprise a plurality of superposed laminations having horizontal shank portions 18 and angularly related toe portions 20 which terminate in substantially horizontal contact faces 22. As shown most clearly in Figs. 1 and 2, three brush members are secured to the lower face of each contact block in spaced parallel relation, with the toe portions thereof mutually inwardly directed. Cap screws 24 pass through the laminations and the jackets 26 which surround the shank portions thereof secured betweenthe spaced. arms of U-shaped contact holders 32. Said contact members are located at similar ends of said stationary.

switch members below and laterally spaced from said contact blocks 14 and 16 and spaced apart from each other, in which position they are supported by and are electrically connected with said switch members by means of depending supporting brackets 3a, one of which is shown most clearly in Fig. 1. Said supporting brackets are secured removably to the vertical seats 36 at the similar ends of said contact blocks by means of cap screws 38 and are formed at their lower ends with an outwardly ottset vertical seat 40. Said brackets are also provided with spaced parallel side webs i2 between which the contact holders 32 are received closely. A single bolt 44 secures each contact holder removably to the lower seat 40 of its bracket. Stationary arcing contact members L6 and 47 are similarly disposed on the opposite sides of said stationary switch members in spaced relation with each other and laterally spaced from said contact blocks 14 and 16. Said arcing members 46 and 4;? are electrically connected together and are mechanically supported free from electrical connection. with said contact blocks by a horizontal conducting bar 48. Said bar is provided with a central cylindrical boss 50 which receives the reduced lower end portion of a supporting and insulating pillar 52 by which it is supported dependingly from the switch frame. Said arcing members are provided with holders 53 which are similar to the holders 32 above described. Said holders 53 are secured by means of bolts 5% to and in good electrical contact with the ends of said bar in which position they are held against displacement by vertical ribs 56 formed on the outer face of said bar.

The movable switch member with which this invention is primarily concerned includes a conducting bridging member 58 of generally rectangular shape which has a fiat upper surface 60 that is adapted to cooperate with the horizontal contact faces 22 of the stationary main contact members whereby to simultaneously connect the stationary switch members through the three pairs of parallel brush members. Marginal slots 62 are formed in said bridging member between the :parallelbrush members at each side thereof which somewhat reduce the weight thereof and also decrease the piston effect of the bridging member as it is moved vertically through the insulating oil in which it is immersed and to facilitate the connection cooling thereof. Said movable switch member also includes a plurality of arcing men1 bers which are adapted to engage and cooperate with the above described pairs of stationary arcing members 28, 30, 4:7 and 4:6 and interrupt the circuit through the switch subsequent to the opening of the main contact members. Said movable switch member is vertically reciprocated by means of a vertical lifting rod 64 which is received loosely in a central aperture in the bridging member and extends therebeneath and terminates in a downwardly and outwardly flared, or conical, end portion 66 which provides an annular shoulder 68 at the upper end thereof. Said lifting rod carries at its lower flared end portion a rigid support comprising a pair of complemental clamping members 70 and 72 which are identical and which are provided with complemental conical recesses which receive the flared end portion 66 of said rod. Said clamping members are provided with spaced upstanding arms 74 which are located on opposite sides of the lifting 1 rod and on which the movable bridging member 58 is pivotally supported. Said bridging member is accordingly provided with a pair of spaced depending flanges 76 and 78 011 either side of the switch rod 64 between which said upstanding arms are received closely. Pivotpins 80extend through aligned apertures in said flanges and the arms 74 and are secured against displacement therein by means of cotter pins. The bridging plate is permitted a certain amount .of pivotal movement so that it can seat itself on all of the brush members. Bolts 82 are provided to fix said clamping members rigidly to the lower end of said rod two of which bolts are passed through laterally outstanding cars 84 of the clamping members at either side of the insulating switch rod.

Each of said clamping members, as shown most clearly in Fig. 4, has a pair of spaced outstanding arms 86 which constitute supporting means for insulating rods 88 which extend horizontally through said arms and outwardly in opposite directions therebeyond. Said arms clamp said insulating rods fixedly in position therebetween and to this end are horizontally split at their extended ends and are provided with clamping bolts 90 which contract said arms into firm engagement with the rods. Said rods are provided with reduced end portions on which are received the supporting brackets 92 for the movable arcing contact members, one of which is shown in detail in Fig. 5. Each of said brackets comprises a split clamp having thecentralpassage94 therethrough to receive the cylindrical end portion of said rods and an offset portion or arm 95 which terminatesin an upstanding boss or ear 96. As shown most clearly in Fi 1, said ofi'set portions '95 are inwardly directed toward each other whereby to locate the upstanding bosses 96 of the contact supports at similar ends of said rods between and spaced a substantial distance from said stationary arcing contact members.

The movable arcing contact members 98 are similar to the fixed arcing contact members and are supported between the bifurcated outer ends 100 of generally horizontal contact arms 102. Said arms are also bifurcated at their inner ends betweenwhich bifurcations the upstanding bosses 96 are received. A pivot pin 104 extends through the having horizontal connection portions 110 which are disposed above and are generally parallel with said contact arms 102 and thedepending vertical portions 112' which extend between the bifurcations 100 of but are free from contact with said arms 102 andare secured by means of clamping bolts 114 rigidly to vertical seats 116 of said brackets 92. Said clamping bolts 114 pass through the clamping portions of said brackets 92 and intercept the circular passage 94 therethrough and are received in suitable notches in the ends of said rods 88 thus in effect to key said contact supports 92 to the ends of said rods. The conducting bar 110 also serves to support the brackets which it connects against angular displacement on the supporting rods 88.

Means are provided normally to bias said movable contact arms 102 upwardly whereby constantly to urge the movable arcing contacts into engagement with their cooperating fixed contact members. To this end compression springs 118 are provided on and encircle the extended ends of pivot pins 104. Said springs include the upper intermediate arm 120 which is disposed beneath and bears against the lower faceof the contact arm 102 and the lower end portions 122 which engage the offset portions 95 of the contact supporting brackets. Said springs are held against displacement on the pins 104 by means of the washers and cotter pins 124 and 126, Fig. 4. U-shaped insulating members 128 are provided on said contact arms intermediate the ends thereof which engage the conducting bars 108 and 109 in the uppermost position of said arms and serve to insulate said arms from the intermediate portions 110 of said movement of the bridging member 58"about the pivot pins 80. To this end the inner depending flanges? 6 are formed with central depending portionswhich terminate in the spacedvertical lugs 130, best shown in Fig. 2. Horizontal ribs'132 are provided at the base of said u standing ears 74 of the clamping members 0 and 72 which are received loosely betweensaid spaced lugs whereby to limit the extent of pivotal movement of said bridging member and prevent said bridging memher from coming in contact with either of said conducting bars 108 and 109.

lhe above described contact structure for the arcing contact members provides four points of circuit interruption which are electrically in series between the studs 10 and 12 of thestationary switch members. Ourrent passing through the switch subsequent to the separation of the main contact members is directed, by reason of the arrangement of the movable arcing members and the current conducting components which support them, to traverse a loop in the vicinity of and including each of said pivotal supporting arcing members. As will be evident from an inspection of Fig. 6, the current passing,

through the support 92 and the movable contact arm 102 is flowing in opposite but parallel directions. thus to set up a strong localized magnetic field which exerts a repulsive effect on said arm 102 in an upward direction; whereas the current flowing in the arm 102 and the intermediate portion 110 of the conducting bar 108 exerts an attractive effect on said arm which also tendsto urge it in an upward direction. By reason of the close spacing ofthe movable arm 102an d the conducting components 92 and 110, sufficient force is exerted on said arm not only to overcome the oppositely acting repulsive effect of the current flowing in the generally U-shaped path through the switch but, in addition, to

to force them outwardly and into intimate contact with the cool body of oil in which the contact members are immersed, thereby to cool and extinguish the arcs rapidly.

Various changes in the construction and arrangement of the parts may be madewithout departing from the scope of the invention.

I claim: 1 I

, 1. A movable switch member for an electric switch including a vertical lifting rod, a supporting member fixed to the lower end of said rod having oppositely extended arms, insulating bars carried by said arms and extended laterally in opposite directions therebeyond, contact supporting brackets carried by the ends of said bars, a rigid conducting member electrically connecting the brackets at similar ends ofsaid bars, and contact members overlying said supporting brackets and having flexible connections therewith at one end by which current traverses said cont-act members and the supporting brackets therefor in opposite directions.

2. A movable switch member for an electric switch including a vertical lifting rod, a supporting member carried by the lower end of said rod having oppositely extended arms, insulating members carried by the ends of said arms and extended in opposite directions therebeyond, conducting brackets carried by the opposite ends of said insulating members, a rigid conducting member overlying the brackets at similar ends of said members, generally horizontal contact members located close to and substantially parallel with said conducting members and having a flexible electrical connection with said brackets at one end thereof .by which current traverses said brackets in directions opposite to the current flowing in said contacts and conducting members.

3. A movable switch member for an electric switch including a lifting rod, clamping members carried by the lower end of said rod each having a pair of outstanding arms, insulating rods carried by said arms and extended in both directions therebeyond, contactsupporting members carried by the ends of said insulating rods having upstanding bosses, pivoted arms carried by said bosses overlying said supports, arcing members at the free ends of said pivoted arms, and rigid conducting members connecting the contact supporting members at similar ends of said insulating rods and having sections overlying said pivoted arms.

4. A movable switch member for a multibreak electric switch comprising a movable supporting structure having a pair of oppositely directed arms, an insulating rod carried by each arm and extended transversely therebeyond in opposite directions, contact supporting members carried by the ends of each rod having inwardly and upwardly directed arms, movable contact members comprising generally horizontal arms pivotally connected at one end to the arms of said supporting members and overlying said support-- ing members, said contact arms having arcing members at their free ends, and rigid current conducting means having horizontal sections which overlie said arms and vertical depending sections which are connected electrically with the supporting members at similar ends of said rods and at the ends thereof remote from the pivotal support of said contact arms.

5. In an electric switch, a movable switch member including a lifting rod, supporting means at the lower end of said rod comprising oppositely directed outstanding arms, insulating bars carried by said arms and extended transversely 1n OPPOSltB directions therebeyond, contact supporting brackets carried by the extended ends of said bars, the brackets on similar ends of said bars being inwardl directed toward each other, rigid conducting members connecting the brackets at similar ends of said bars, said members having an intermediate horizontal portion which overlies said brackets and integral depending sections which are secured to said brackets at the outermost ends thereof, movable contact members comprising generally horizontal arms disposed between said conducting members and brackets and having flexible connections with said brackets at the innermost ends thereof, said contact members being extended outwardly beyond the depending sections of said conducting members, and arcing contact members carried by the extended ends thereof.

6. I11 an electric switch, a movable switch member comprising a lifting rod, a supporting structure carried bythe lower end of said rod having oppositely directed outstanding arms, insulating bars carried by the extended ends of said arms and extended transversely in opposite directions therebeyond, contact supporting brackets carried by the extended ends of said bars having clamping portions by which they are secured fixedly to said bars and having inwardly directed arms, a rigid conducting member electrically connecting the clamping portions of said brackets which are disposed at similar ends of said rods, movable contact members comprising generally horizontal arms having a flexible connection with the arms of said brackets at the ends thereof and extended outwardly beyond and free from contact with said conducting member, and arcing contact members carried by the extended ends of said contact arms.

7. In an electric switch, a movable switch member comprising a lifting rod, a support ing structure carried by said rod at the lower end thereof having oppositely directed outstanding arms, insulating bars carried by the extended ends of said arms and extended transversely in opposite directions therebeyond, a main contact member comprising abridging member carried by said supporting structure, an auxiliary contact structure carried by the similar ends of said insulating bars beneath saidbridging member comprising brackets fixed to the ends of said bars having inwardly directed arms, contact members comprising generally horizontal arms having a flexible connection with and overlying the arms of said brackets, a rigid conducting member electrically connecting said brackets at the outermost ends thereof having a horizontal section thereof which is disposed above said movable contact arms, and arcing contact members carried by the free ends of saidcontact arms. 1

8. In an electric switch, a movable switch member comprising a lifting rod, a Supportture through havlng mutually inwardly directed arms,

contact members comprising generallyhorizontal arms having flexible connections at their inner ends on the ends of said inwardlydirected arms, said contact arms arranged to overlie said bracketsand having bifurcated outer ends which extend outwardly beyond said brackets, arcing contact members carried by the bifurcated ends of said arms, and a rigid conductor connecting said brackets having an intermediate horizontal portion'which is disposed above and overlies said contact arms and depending'end portions which pass throu h the bifurcations of said arms.

, 9. I n an electric switch, a movable switch member comprising a lifting rod, a supporting structure carried by said rod at the lower end thereof having oppositely directed outstanding arms, insulating bars carried by the extended ends of said arms and extended transversely in opposite directions therebeyond, an auxiliary contact structure carried at the similar ends of said bars comprising contact supporting brackets fixed to the ends of said bars having inwardly directed arms terminating in upstanding bosses, movable contact'members comprising generally horizontal arms overlying said brackets and having bifurcated outer end portions which extend beyond said brackets, arcing contact members carried by the bifurcated ends of said arms, 'anda rigid conducting member electrically connecting said brackets including a horizontal portion which overlies said contact arms and depending end portions which extend through and are free from com tact with the bifurcations of said arms and are electrically connected with said brackets at the outer ends thereof.

e 10. In an electric switch, a movable switch member comprisingla lifting rod, clamping members fixed to t e lower end of said rod having oppositely directed outstanding arms, lugs upstanding from said armsintermediate the ends thereof, a main contact member comprising a bridging member having an aperwhich said rod extends, means pivotally supporting said bridging member on said upstanding lugs, insulating bars carried by said arms and extended transversely in opposite directions therebeyond, and arcs ing contact structure carried by the similar ends of said bars including fixed conducting brackets carried by said bars and havinginwardly directed arms, a rigid conducting member havinga horizontal portion, which is located above and generally parallel with said brackets and a pair of depending end portions which are fixed at their lower ends to the outermost ends of said brackets, movable contact members comprising generally horizontal arms having a pivotal connection at one end thereof on the armsv of said brackets and having bifurcated outer end portions which extend on opposite sides of and beyond the depending portions of said conducting members, and arcing contact members carried by the extended ends of said contact arms.

11. In an electric switch, a movable switch member comprising a lifting rod, clamping members fixed to the lowerend of said rod having oppositely directed outstanding arms, lugs upstanding from said arms intermediate the ends thereof, a main contact member comprising a bridging member having an aperture through which said rod extends, means pivotally supporting said bridging member on said upstanding lugs, insulating bars carried by said arms and extended transversely in opposite directions therebeyond, and areing contact structures carried by the similar ends of said bars including fixed conducting brackets carried'by said bars and having inwardly directed arms, a rigid conducting member having a horizontal portion which is located above and generally parallel with said brackets and a pair of depending end portions which are fixed at their lower ends to the outermost ends of said brackets, movable contact members comprising generally horizontal arms having a pivotal connection at one end thereof on the arms of said brackets and outer end portions which extend on opposite sides of and beyond the depending portions of said conducting member, arcing contact members carried by the extended ends of said contact arms, resilient means normallybiasing said contact members in an upward direction, and insulating means interposed between said contact members and conducting support constituting stops to limit the upward movement of said contact arms.

12. In an electric switch, a movable switch member comprising a vertical lifting rod, complemental clamping members secured to the lower end of said rod, said clamping mem-- bers having oppositely and outwardly directed brackets which terminate in spaced parallel arms, insulating bars carried by said arms and extended transversely in opposite directions therebeyond, an upstanding'lug carried by each of said brackets intermediate its ends, a main bridging member having a central aperture through which said rod extends, means pivotally supporting said bridging member on said lugs, and an arcing contactv structure carried by the similar ends of said insulating bars and duplicated at opposite sides of said lifting rod comprising contact supporting members having intermediate clamping portions which are fixed to the end of said insulating bars and mutually inwardly directed arms, generally horizontal contact arms having a pivotal connection at their inner ends on the arms of said contact supporting members and extended outwardly therebeyond, a rigid conducting member having a horizontal portion which is located above and generally parallel with said contact arms and depending end portions which are connected electrically with said contact supporting members at the outermost ends thereof, and electrical conducting means connecting the juxtaposed ends of the arms of said supports and the contact member carried thereby whereby to direct current to flow in a direction in said support which is opposite to the direction of the current traversing said cont-act member and the horizontal portion. of said conducting member.

13. In an electric switch, the combination of a pair of spaced stationary contact members, a movable switch member having a contact supporting structure at its lower end including a pair of horizontal insulating bars, conducting brackets carried by the similar ends of sai d bars having mutually inwardly directed arms which terminate in upstanding bosses, pivoted contact arms overlying said brackets and the extended arms thereof and having a pivotal connect-ion at one end thereof on said bosses, cont-act members carried by said arms at the free ends thereof which are disposed below and are arranged to cooperate with said spaced stationary contact members, and means to direct current to flow in opposite directions through said brackets and their pivotally supported contact arms including a rigid conductor which electrically connects said brackets at the outermost ends thereof, said conducting member being disposed mainly above and in parallel relation with said contact arms.

14. In an electric switch, the combination of spaced stationary switch members, stationary contact members carried thereby, an insulating pillar located between and at one side of said stationary switch members having a transverse conducting member at its lower end, the extended ends of said conducting member being equi-distant from said stationary contact members, stationary contact members carried by the ends of said conducting member, a movable switch member including a vertical lifting rod having a rigid supporting structure at its lower end comprising a pair of clamping members having oppositely and outwardly directed arms, insulating bars carried by said arms and extended transversely in both directions therebeyond, each of said bars being disposed beneath and parallel with a. pair of stationary contact members, contact supporting means carried by the ends of said bars including a clamping portion and an inwardly directed conducting portion which terminates in an upstanding boss, generally horizontal contactarms having a pivotal connection at their inner ends on said bosses and arranged to overlie the conductposed mainly above and are parallel with the conducting portions of said contact supporting means, whereby to direct current to flow in parallel paths through said cont-act supporting means and the contact arms thereof.

15. A movable switch member for a multibreak electric switch comprising a vertically movable supporting structure having a pair of outstanding arms, means rigidly connecting said arms to extend in opposite directions, a lifting rod clamped between said arms, an insulating rod carried by the end of each arm and extended transversely in opposite directions therebeyond, contact supporting members carried insulating rods comprising a horizontal clamping portion and an integral upwardly and inwardly directed bracket, a movable contact member comprising a generally horizontal arm which is pivotally connected at its inner end to the end of said bracket, arcing members carried at the free ends of said arms, and rigid electrical conducting means connecting the contact sup porting members which are located at similar ends of said rods, said means including a horizontal portion which is parallel with and overlies the similarly located contact arms, and depending vertical end portions which are connected separately with the ends of said contact supporting members adjacent the free ends of said arms.

16. An electricswitch having stationary switch members including a pair of stationary contact members, a movable switch member including a pair of brackets each having a transverse central support and outwardly and inwardly directed arms, oppositely extended contact arms having pivotal connections at their inner ends with and overlying said inwardly directed bracketarms an having contact members at their outer ends which engage said stationary contact members, and a conductor which electrically connects the outwardly directed arms of said brackets, the current traversing said brackets and contact arms forcing said movable contact members into engagement with said stationary contact members.

17. An electric switch having stationary by the ends of said a switch members including a pair of stationary contact members, a movable switch member including a pair of brackets each having a transverse central support and out-'- wardly and inwardly directed arms, 0ppositely extended contact arms having pivotal connections at their inner ends with and overlying said inwardly-directed bracketarms and having contact members at their outer ends which engage said stationarycontact members, and a conductor which overlies said contact arms and which electrically connects the outwardly directed arms of said brackets, the current traversing said 15 bracket and contact arms and said conductor forcing said contact arms toward said stationary contact members.

In testimony whereof, I have signed my name to this specification. CHESTER D. AINSWORTH. 

